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Prediction of shield tunneling-induced ground settlement using machine learning techniques

Renpeng CHEN, Pin ZHANG, Huaina WU, Zhiteng WANG, Zhiquan ZHONG

《结构与土木工程前沿(英文)》 2019年 第13卷 第6期   页码 1363-1378 doi: 10.1007/s11709-019-0561-3

摘要: Predicting the tunneling-induced maximum ground surface settlement is a complex problem since the settlement depends on plenty of intrinsic and extrinsic factors. This study investigates the efficiency and feasibility of six machine learning (ML) algorithms, namely, back-propagation neural network, wavelet neural network, general regression neural network (GRNN), extreme learning machine, support vector machine and random forest (RF), to predict tunneling-induced settlement. Field data sets including geological conditions, shield operational parameters, and tunnel geometry collected from four sections of tunnel with a total of 3.93 km are used to build models. Three indicators, mean absolute error, root mean absolute error, and coefficient of determination the ( ) are used to demonstrate the performance of each computational model. The results indicated that ML algorithms have great potential to predict tunneling-induced settlement, compared with the traditional multivariate linear regression method. GRNN and RF algorithms show the best performance among six ML algorithms, which accurately recognize the evolution of tunneling-induced settlement. The correlation between the input variables and settlement is also investigated by Pearson correlation coefficient.

关键词: EPB shield     shield tunneling     settlement prediction     machine learning    

Identification of abnormal operating conditions and intelligent decision system

Xiuliang LI, Junjie JIANG, Hongye SU, Jian CHU

《机械工程前沿(英文)》 2011年 第6卷 第4期   页码 456-462 doi: 10.1007/s11465-011-0224-0

摘要:

In earth pressure balance (EPB) shield construction, the “plastic flow state” is difficult to form using the soil dug in the capsule because it can cause three abnormal operating conditions, including occlusion, caking in the capsule, and spewing at the outlet of the dump device. These abnormal operating conditions can, in turn, trigger failure in tunneling, cutter-device damage, and even catastrophic incidents, such as ground settlement. This present paper effectively integrates the mechanism of abnormal operating conditions and knowledge of soil conditioning, and establishes a uniform model of identifying abnormal conditions and intelligent decision support system based on the belief rule-base system. The model maximizes knowledge in improving the soil, construction experience, and data to optimize the model online. Finally, a numerical simulation with specific construction data is presented to illustrate the effectiveness of the algorithm.

关键词: earth pressure balance (EPB) shield machine     soil pressure cabin     abnormal operating condition     belief rule-base system    

Deviation correction strategy for the earth pressure balance shield based on shield–soil interactions

《机械工程前沿(英文)》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0676-4

摘要: The control system presently used in shield posture rectification is based on driver experience, which is marginally reliable. The study of the related theory is flawed. Therefore, a decision-making approach for the deviation correction trajectory and posture rectification load for an earth pressure balance (EPB) shield is proposed. A calculation model of posture rectification load of an EPB shield is developed by considering the interactions among the cutter head, shield shell, and ground. The additional position change during the shield attitude correction is highlighted. The posture rectification loads and shield behaviors results can be solved by the proposed method. The influences of the stratum distribution (i.e., bedrock height in the upper-soft and lower-hard strata) on shield behaviors and posture rectification loads are analyzed. Results indicated that the increase of pitch angle in the upper-soft and lower-hard strata causes a sharp rise in vertical displacement. The bedrock height increases the magnitudes of the required posture rectification moments when hr/D > 0.5. For a tunnel with hr/D ≤ 0.5, the variation of hr/D has little effect on the posture rectification moments. Finally, the posture rectifying curves based on the theoretical model are compared with the target ones based on the double circular arc interpolation method. The required results can be obtained regardless of the soil–rock compound stratum distribution. The maximum rectification moment in the rock layer is almost 12.6 times that in the soil layer. Overall, this study provides a valuable reference for moment determination and the trajectory prediction of posture rectification in compound strata.

关键词: additional position change     deviation correction trajectory     earth pressure balance shield     mechanical model     posture rectification    

Deformation control criterion of shield tunnel under lateral relaxation of soft soil

《结构与土木工程前沿(英文)》 2023年 第17卷 第5期   页码 780-795 doi: 10.1007/s11709-023-0944-3

摘要: Metro shield tunnels under the lateral relaxation of soil (LRS) are susceptible to significant lateral deformations, which jeopardizes the structural safety and waterproofing. However, deformation control standards for such situations have not been clearly defined. Therefore, based on a specific case, a model test is conducted to realize the LRS of a shield tunnel in a sandy stratum to reveal its effect on segment liners. Subsequently, a deformation control criterion is established. The LRS is simulated by linearly reducing the loads applied to the lateral sides of the segment structure. During lateral unloading, the lateral earth pressure coefficient on the segment decreases almost exponentially, and the structural deformation is characterized by horizontal expansion at the arch haunches and vertical shrinkage at the arch vault and arch bottom. Based on the mechanical pattern of the segment structure and the acoustic emission, the deformation response of a segment can be classified into three stages: elastic and quasi-elastic, damage, and rapid deformation development. For a shield tunnel with a diameter of approximately 6 m and under the lateral relaxation of sandy soil, when the ellipticity of the segment is less than 2.71%, reinforcement measures are not required. However, the segment deformation must be controlled when the ellipticity is 2.71% to 3.12%; in this regard, an ellipticity of 3% can be used as a benchmark in similar engineering projects.

关键词: shield tunnel     lateral relaxation of soil     deformation control criterion of segment structure     model test    

A real-life stability model for a large shield-driven tunnel in heterogeneous soft soils

Xinyu HU, Zixin ZHANG, Scott KIEFFER

《结构与土木工程前沿(英文)》 2012年 第6卷 第2期   页码 176-187 doi: 10.1007/s11709-012-0149-7

摘要: The current models that have been published to date only allow for homogeneous soil at the tunnel face. This paper presents a real-life face stability model to determine the minimal pressure needed at the tunnel face for a large shield-driven tunnel in heterogeneous soft soils. It is found that the influence of multilayered soil boundaries is significant, especially for the mixed-layer (e.g., sand and clay) soils. The suggested M-M model is developed by considering the influence of the heterogeneity of the soil on the angle of slip and the minimal support pressure. Comparisons of the solutions in mixed-layer soils are conducted, and the effects of the involved parameters for a large, multilayered, shield-driven tunnel are also investigated.

关键词: analytical solution     shield-driven tunnel     multilayered soil     face stability    

Experimental study on slurry-induced fracturing during shield tunneling

Teng WANG, Dajun YUAN, Dalong JIN, Xinggao LI

《结构与土木工程前沿(英文)》 2021年 第15卷 第2期   页码 333-345 doi: 10.1007/s11709-021-0718-8

摘要: Facial support in slurry shield tunneling is provided by slurry pressure to balance the external earth and water pressure. Hydraulic fracturing may occur and cause a significant decrease in the support pressure if the slurry pressure exceeds the threshold of the soil or rock material, resulting in a serious face collapse accident. Preventing the occurrence of hydraulic fracturing in a slurry shield requires investigating the effects of related influencing factors on the hydraulic fracturing pressure and fracture pattern. In this study, a hydraulic fracturing apparatus was developed to test the slurry-induced fracturing of cohesive soil. The effects of different sample parameters and loading conditions, including types of holes, unconfined compressive strength, slurry viscosity, and axial and circumferential loads, on the fracturing pressure and fracture dip were examined. The results indicate that the fracture dip is mainly affected by the deviator stress. The fracturing pressure increases linearly with the increase in the circumferential pressure, but it is almost independent of the axial pressure. The unconfined compressive strength of soil can reflect its ability to resist fracturing failure. The fracturing pressure increases with an increase in the unconfined compressive strength as well as the slurry viscosity. Based on the test results, an empirical approach was proposed to estimate the fracturing pressure of the soil.

关键词: slurry shield tunneling     hydraulic fracturing test     fracturing pressure     fracture dip     unconfined compressive strength     slurry viscosity    

Discontinuous mechanical behaviors of existing shield tunnel with stiffness reduction at longitudinal

《结构与土木工程前沿(英文)》 2023年 第17卷 第1期   页码 37-52 doi: 10.1007/s11709-022-0920-3

摘要: An analytical model is proposed to estimate the discontinuous mechanical behavior of an existing shield tunnel above a new tunnel. The existing shield tunnel is regarded as a Timoshenko beam with longitudinal joints. The opening and relative dislocation of the longitudinal joints can be calculated using Dirac delta functions. Compared with other approaches, our method yields results that are consistent with centrifugation test data. The effects of the stiffness reduction at the longitudinal joints (α and β), the shearing stiffness of the Timoshenko beam GA, and different additional pressure profiles on the responses of the shield tunnel are investigated. The results indicate that our proposed method is suitable for simulating the discontinuous mechanical behaviors of existing shield tunnels with longitudinal joints. The deformation and internal forces decrease as α, β, and GA increase. The bending moment and shear force are discontinuous despite slight discontinuities in the deflection, opening, and dislocation. The deflection curve is consistent with the additional pressure profile. Extensive opening, dislocation, and internal forces are induced at the location of mutation pressures. In addition, the joints allow rigid structures to behave flexibly in general, as well as allow flexible structures to exhibit locally rigid characteristics. Owing to the discontinuous characteristics, the internal forces and their abrupt changes at vulnerable sections must be monitored to ensure the structural safety of existing shield tunnels.

关键词: tunnel–soil interaction     discontinuous analysis     longitudinal joints     existing shield tunnel     Timoshenko beam     Dirac delta function    

Analysis of load and adaptability of disc cutters during shield tunneling in soft–hard varied strata

《结构与土木工程前沿(英文)》 2023年 第17卷 第4期   页码 533-545 doi: 10.1007/s11709-023-0946-1

摘要: The disc cutters of shield machines exhibit unsatisfactory adaptability and performance during the soft–hard varied strata tunneling process. To analyze the rotation state, cutting performance, and adaptability of disc cutters during shield tunneling in soft–hard varied strata, the Holmquist Johnson Cook and Federal Highway Administration constitutive models are introduced to numerically simulate the failure process of materials on the excavation face and to calculate the load of disc cutters. Additionally, the parameters of the models are modified based on laboratory disc cutter excavation test results. The results of numerical calculation can reflect the load level and the behavior of the disc cutters during operation. The tangential loads of the disc cutters during the cutting of four typical soft-strata excavation face models are numerically calculated, thus providing reference values for the starting torque of the disc cutters. A greater penetration is suggested for soft-strata tunneling to allow the disc cutters to rotate smoothly and continuously as well as to guarantee a better cutting effect. The disc cutters in the center of the cutterhead should be specified with a lower starting torque to prevent uneven wear, rotation stagnation, cutterhead clogging, and other adverse phenomena.

关键词: shield tunneling     disc cutter load     laboratory excavation test     numerical calculation     soft–hard varied strata    

Weakening behavior of waterproof performance in joints of shield tunnels under adjacent constructions

《结构与土木工程前沿(英文)》   页码 884-900 doi: 10.1007/s11709-022-0912-3

摘要: Groundwater leakage in shield tunnels poses a threat to the safety and durability of tunnel structures. Disturbance of adjacent constructions during the operation of shield tunnels frequently occurs in China, leading to deformation of tunnel lining and leakage in joints. Understanding the impact of adjacent constructions on the waterproofing performance of the lining is critical for the protection of shield tunnels. In this study, the weakening behavior of waterproof performance was investigated in the joints of shield tunnels under transverse deformation induced by adjacent construction. First, the relationship between the joint opening and transverse deformation under three typical adjacent constructions (upper loading, upper excavation, and side excavation) was investigated via elaborate numerical simulations. Subsequently, the evolution of the waterproof performance of a common gasket with a joint opening was examined by establishing a coupled Eulerian–Lagrangian model of joint seepage, and a formula describing the relationship between waterproof performance and joint opening was proposed. Finally, the weakening law of waterproofing performance was investigated based on the results of the aforementioned studies. It was determined that the joints with the greatest decline in waterproof performance were located at the tunnel shoulder in the upper loading case, tunnel crown in the upper excavation case, and tunnel shoulder in the side excavation case. When the waterproof performance of these joints decreased to 50% and 30%, the transverse deformations were 60 and 90 mm under upper loading, 90 and 140 mm under upper excavation, and 45 and 70 mm under side excavation, respectively. The results provide a straightforward reference for setting a controlled deformation standard considering the waterproof performance.

关键词: shield tunnel     waterproof performance     horizontal transverse deformation     joint opening     weakening behavior    

Manufacturing technique and performance of functionally graded concrete segment in shield tunnel

Baoguo MA, Dinghua ZOU, Li XU

《结构与土木工程前沿(英文)》 2009年 第3卷 第1期   页码 101-104 doi: 10.1007/s11709-009-0011-8

摘要: The quality of segment is very important to the service life of shield tunnel. Concerning the complex engineering environment of the Wuhan Yangtze River Shield Tunnel, the principle of functionally graded materials was introduced to design and produce the functionally graded concrete segment (FGCS). Its key manufacturing technique was proposed and its performance was tested.

关键词: shield tunnel     functionally graded concrete segment (FGCS)     manufacturing technology     performance    

Effect of cutterhead configuration on tunnel face stability during shield machine maintenance outages

《结构与土木工程前沿(英文)》 2023年 第17卷 第4期   页码 522-532 doi: 10.1007/s11709-023-0930-9

摘要: Owing to long-distance advancement or obstacles, shield tunneling machines are typically shut down for maintenance. Engineering safety during maintenance outages is determined by the stability of the tunnel face. Pressure maintenance openings are typically used under complicated hydrogeological conditions. The tunnel face is supported by a medium at the bottom of the excavation chamber and compressed air at the top. Owing to the high risk of face failure, the necessity of support pressure when cutterhead support is implemented and a method for determining the value of compressed air pressure using different support ratios must to be determined. In this study, a non-fully chamber supported rotational failure model considering cutterhead support is developed based on the upper-bound theorem of limit analysis. Numerical simulation is conducted to verify the accuracy of the proposed model. The results indicate that appropriately increasing the specific gravity of the supporting medium can reduce the risk of collapse. The required compressed air pressure increases significantly as the support ratio decreases. Disregarding the supporting effect of the cutterhead will result in a tunnel face with underestimated stability. To satisfy the requirement of chamber openings at atmospheric pressure, the stratum reinforcement strength and range at the shield end are provided based on different cutterhead aperture ratios.

关键词: tunnel face stability     cutterhead configuration     aperture ratio     pressure gradient     support ratio    

A redundantly actuated PRPRP radial mechanism in the segment erector of a shield machine for synchronization

Wanghui BU, Zhenyu LIU, Jianrong TAN, Jin CHENG

《机械工程前沿(英文)》 2011年 第6卷 第4期   页码 463-467 doi: 10.1007/s11465-011-0225-z

摘要:

The shield machine is a heavy construction machine for tunnel excavation, and the segment erector is an important subsystem of the shield machine. It is difficult to achieve precise control in the 6-DOF (degree of freedom) erector in the 2-DOF 5-bar radial mechanism. Hence, this paper proposes a redundantly actuated PRPRP radial mechanism for the segment erector. When the redundant actuator is unlocked, the radial mechanism is able to adjust its posture, which has two degrees of freedom. On the other hand, when the redundant actuator is locked or produces enough pre-tightening tensile force, the PRPRP mechanism can ensure the synchronization of the two driving hydraulic cylinders along the radial direction based on the mechanical structure, which has one degree of freedom. The redundant actuator also facilitates the equal application of two flexural torques at the hydraulic cylinders; thus, preventing the overload of a single cylinder.

关键词: redundant actuation     parallel mechanisms     five-bar mechanisms     segment erectors     shield machines    

Clogging of slurry-shield tunnel-boring machine drives in sedimentary soft rock: A case study

《结构与土木工程前沿(英文)》 doi: 10.1007/s11709-023-0984-8

摘要: This paper presents a case study of the clogging of a slurry-shield tunnel-boring machine (TBM) experienced during tunnel operations in clay-rich argillaceous siltstones under the Ganjiang River, China. The clogging experienced during tunneling was due to special geological conditions, which had a considerably negative impact on the slurry-shield TBM tunneling performance. In this case study, the effect of clogging on the slurry-shield TBM tunneling performance (e.g., advance speed, thrust, torque, and penetration per revolution) was fully investigated. The potential for clogging during tunnel operations in argillaceous siltstone was estimated using an existing empirical classification chart. Many improvement measures have been proposed to mitigate the clogging potential of two slurry-shield TBMs during tunneling, such as the use of an optimum cutting wheel, a replacement cutting tool, improvements to the circulation flushing system and slurry properties, mixed support integrating slurry, and compressed air to support the excavation face. The mechanisms and potential causes of clogging are explained in detail, and the contributions of these mitigation measures to tunneling performance are discussed. By investigating the actual operational parameters of the slurry-shield TBMs, these mitigation measures were proven to be effective in mitigating the clogging potential of slurry-shield TBMs. This case study provides valuable information for slurry-shield TBMs involving tunneling in clay-rich sedimentary rocks.

关键词: slurry-shield TBM     geological investigation     clogging     argillaceous siltstone     TBM performance     mitigation measures    

Numerical and experimental analyses of methane leakage in shield tunnel

《结构与土木工程前沿(英文)》   页码 1011-1020 doi: 10.1007/s11709-023-0956-z

摘要: Tunnels constructed in gas-bearing strata are affected by the potential leakage of harmful gases, such as methane gas. Based on the basic principles of computational fluid dynamics, a numerical analysis was performed to simulate the ventilation and diffusion of harmful gases in a shield tunnel, and the effect of ventilation airflow speed on the diffusion of harmful gases was evaluated. As the airflow speed increased from 1.8 to 5.4 m/s, the methane emission was diluted, and the methane accumulation was only observed in the area near the methane leakage channels. The influence of increased ventilation airflow velocity was dominant for the ventilation modes with two and four fans. In addition, laboratory tests on methane leakage through segment joints were performed. The results show that the leakage process can be divided into “rapid leakage” and “slight leakage”, depending on the leakage pressure and the state of joint deformation. Based on the numerical and experimental analysis results, a relationship between the safety level and the joint deformation is established, which can be used as guidelines for maintaining utility tunnels.

关键词: shield tunnel     harmful gas leakage     numerical analysis     laboratory test    

Bending failure performance of a shield tunnel segment based on full-scale test and numerical analysis

《结构与土木工程前沿(英文)》   页码 1033-1046 doi: 10.1007/s11709-023-0973-y

摘要: This study focuses on the bending failure performance of a shield tunnel segment. A full-scale test was conducted to investigate deformation and failure characteristics. During the loading, the bending failure process can be divided into four stages: the elastic stage, working stage with cracks, failure stage, and ultimate stage. The characteristic loads between contiguous stages are the cracking, failure, and ultimate loads. A numerical model corresponding to the test was established using the elastoplastic damage constitutive model of concrete. After a comparative analysis of the simulation and test results, parametric studies were performed to discuss the influence of the reinforcement ratio and proportion of tensile longitudinal reinforcement on the bearing capacity. The results indicated that the change in the reinforcement ratio and the proportion of tensile longitudinal reinforcement had little effect on the cracking load but significantly influenced the failure and ultimate loads of the segment. It is suggested that in the reinforcement design of the subway segment, the reinforcement ratio and the proportion of tensile longitudinal reinforcement can be chosen in the range of 0.7%–1.2% and 49%–55%, respectively, allowing the segment to effectively use the reinforcement and exert the design strength, thereby improving the bearing capacity of the segment.

关键词: shield tunnel     bearing capacity     failure mechanism     segment reinforcement    

标题 作者 时间 类型 操作

Prediction of shield tunneling-induced ground settlement using machine learning techniques

Renpeng CHEN, Pin ZHANG, Huaina WU, Zhiteng WANG, Zhiquan ZHONG

期刊论文

Identification of abnormal operating conditions and intelligent decision system

Xiuliang LI, Junjie JIANG, Hongye SU, Jian CHU

期刊论文

Deviation correction strategy for the earth pressure balance shield based on shield–soil interactions

期刊论文

Deformation control criterion of shield tunnel under lateral relaxation of soft soil

期刊论文

A real-life stability model for a large shield-driven tunnel in heterogeneous soft soils

Xinyu HU, Zixin ZHANG, Scott KIEFFER

期刊论文

Experimental study on slurry-induced fracturing during shield tunneling

Teng WANG, Dajun YUAN, Dalong JIN, Xinggao LI

期刊论文

Discontinuous mechanical behaviors of existing shield tunnel with stiffness reduction at longitudinal

期刊论文

Analysis of load and adaptability of disc cutters during shield tunneling in soft–hard varied strata

期刊论文

Weakening behavior of waterproof performance in joints of shield tunnels under adjacent constructions

期刊论文

Manufacturing technique and performance of functionally graded concrete segment in shield tunnel

Baoguo MA, Dinghua ZOU, Li XU

期刊论文

Effect of cutterhead configuration on tunnel face stability during shield machine maintenance outages

期刊论文

A redundantly actuated PRPRP radial mechanism in the segment erector of a shield machine for synchronization

Wanghui BU, Zhenyu LIU, Jianrong TAN, Jin CHENG

期刊论文

Clogging of slurry-shield tunnel-boring machine drives in sedimentary soft rock: A case study

期刊论文

Numerical and experimental analyses of methane leakage in shield tunnel

期刊论文

Bending failure performance of a shield tunnel segment based on full-scale test and numerical analysis

期刊论文